The present invention relates to an apparatus for treating the surface of boards, and more particularly to an apparatus for treating the surface of boards capable of separating completely a waste treating solution and a waste rinse liquid after treating the surface of boards, and regenerating (repreparing) the collected waste treating solution to a treating solution for recycling the treating solution.
In the manufacture of various electronic devices (elements) such as semiconductor devices and liquid crystal display devices, in the first place, a thin film of insulator layer, semiconductor layer and a conductor layer are formed on the surface of the substrate. Next, after applying a resist layer on formed thin film, the layer is exposed by a photo mask, and patterned by a developing solution and an etching solution. Then, by applying a resist stripping solution, the resist left over on the board surface is removed. Further, on the board surface, a rinse liquid (such as isopropyl alcohol, other alcohol, pure water, or the like) is applied, and fine resist particles and treating solution still remaining on the surface are removed. Thus, in manufacture of electronic devices (elements), the operation is conducted in a wet process using a plurality of treating solutions and a rinse liquid.
In this wet process, boards such as wafers are treated by (1) a method of immersing directly in a treating bath containing a treating solution and a rinsing bath containing a rinse liquid, (2) a method of using a spinner fixed on a rotatable wafer chuck for treating the entire board by applying the treating solution and rinse liquid on the board surface sequentially by spray nozzles or straight nozzles, and making use of the rotation of a wafer chuck, (3) a method of disposing boards on the roller conveyor, and applying the treating solution and rinse liquid sequentially in the treating direction of the boards, or (4) a method of disposing multiple boards on a cassette, and applying the treating solution and rinse liquid sequentially on the boards surface by spray nozzles.
In this technique of immersion, however, there was a problem of change of concentration of ingredients in the treating solution in the course of treating multiple wafers, and stable surface treatment was impossible. In the case of using a spinner or a roller conveyor, on the other hand, it produces a tremendous volume of waste liquid mixing waste liquid of treating solution (waste treating solution) and waste liquid of rinse liquid (waste rinse liquid).
Various spinners have been proposed for separating the mixed liquid of treated boards into a waste treating solution and a waste rinse liquid.
For example, the official gazette of Provisional Publication No. 190442/93 discloses a spinner having double cups including an outside cup and an inside cup disposed on the circumference of the wafer chuck. In this spinner, the inside cup is free to move up and down, and a plurality of treating solutions can be separated and collected by the vertical movement of the inside cup. The separated and collected waste treating solutions can be easily discarded or recycled.
The official gazette of Provisional Publication No. 88168/96 discloses a spinner in which an elevatable inner ring is provided on the circumference of the wafer chuck, when the inner ring is positioned in the upper part, its lower end is inside of the partition wall, and when the inner ring is positioned in the lower part, its lower end is outside of the partition wall.
On the other hand, the official gazette of Provisional Publication No. 283395/93 discloses a purifying apparatus of thin materials for applying a treating solution to the boards fixed on a rotatable supporter through a stock container, and collecting the waste treating solution and sending back to the stock container. This purifying apparatus can recycle the treating solution.
The official gazette of Japanese Patent No. 2602179 discloses a resist stripping solution control apparatus, using alkanolamine and organic solvent as the treating solution, for detecting the alkanolamine concentration in a waste treating solution (waste resist stripping solution) by an absorption photometer, and regenerating the treating solution by supplementing (replenishing) insufficient ingredients. Further, the official gazette of Provisional Publication No. 22261/98 discloses a resist stripping solution control apparatus, using alkanolamine, organic solvent and pure water as the treating solution, for detecting the pure water concentration in a waste treating solution (waste resist stripping solution) by an absorption photometer, and regenerating the treating solution by supplementing insufficient ingredients. These control apparatuses can detect and supplements specific ingredients in the treating solution, so that the treating solution always having a specific treating performance can be prepared without deteriorating the treating solution.
However, the spinner disclosed in the official gazette of Provisional Publication No. 190442/93 only separates and collects the waste treating solution, and the ingredients concentration in the treating solution may be changed while repeating circulation of treating solution or waste treating solution, and thereby the treating capacity of boards may be lowered.
The apparatus disclosed in the official gazette of Provisional Publication No. 283395/93 merely sends back the waste treating solution to the stock container, and the ingredients concentration in the treating solution may be changed while repeating circulation of treating solution or waste treating solution, and thereby the treating capacity of boards may be lowered.
Similarly, the spinner disclosed in the official gazette of Provisional Publication No. 88168/96 only separates and collects the waste treating solution, and the ingredients concentration in the treating solution may be changed while repeating circulation of treating solution or waste treating solution, and thereby the treating capacity of boards may be lowered.
In the control apparatuses in the official gazette of Japanese Patent No. 2602179 and the official gazette of Provisional Publication No. 22261/98, when applied in the apparatus for treating surface of boards using the spinner, the rinse liquid is mostly used in the quantity same as or more than the treating solution, and the waste treating solution cannot be separated and collected, and the concentration of the effective ingredients is substantially lowered by dilution, and it produces too much waste from the viewpoint of efficiency of regeneration.
In the resist stripping process of semiconductor boards and liquid crystal boards, a dry ashing process by oxygen plasma and a wet stripping process by resist stripping solution are combined. In the boards after the dry ashing process by oxygen plasma, metal oxides such as obstinate resist degenerated matter and silicon oxide are left over, and it is hard to remove all of them completely in the subsequent wet rest stripping process. It is attempted to raise the temperature of treating solution or extend the treating time, but it brings about a safety problem, and there is other problem from the viewpoint of production efficiency. To raise the physical treating capacity, it is proposed to use a spinner and apply the treating solution at a pressure of about 0.5 to 5 kg/cm.sup.2 G on the surface, and it is expected to enhance the treating capacity by the synergetic effects of rotatable spinner and pressure spraying.
Further, by using a plurality of spinners, it is also proposed to treat with the treating solution and rinse liquid separately by individual spinners, but the size of the apparatus for treating surface of boards is increased, and it is not realistic.
On the other hand, when the treating solution and rinse liquid are treated by a same spinner, the control apparatus may not be used as mentioned, and actually products may not be produced.
In this background there is an increasing demand for reducing the size of the apparatus for treating surface of boards and the control apparatus, using the treating solution sufficiently, recycling the treating solution effectively, applying the rinse liquid immediately after treatment with the treating solution, and decreasing the amount of waste treating solution.